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3-D fluid-mud dynamics in the Jiaojiang Estuary, China 总被引：3，自引：0，他引：3
A 3-D model has been developed for the muddy Jiaojiang Estuary and adjoining coastal waters, and verified against field observations. To simulate fluid-mud formation, the model uses a fine resolution grid near the bottom and involves coupling processes between hydrodynamics and fluid mud such as the sediment-induced buoyancy, increasing turbulent kinetic energy sink and kinematic viscosity, mixing by internal waves riding on the lutocline, and non-Newtonian properties of fluid mud. The effective hydrodynamic drag was reduced in the presence of fluid mud. It is shown that the estuary is infilled by tidal pumping and that longitudinal and transversal gradients of suspended sediment concentration, salinity, and currents control the formation of mud banks. Thus a 3-D model is necessary to estimate the fate of mud, although the model results are very sensitive to details of the parameterization of the hydrodynamics-mud feedback processes. 相似文献
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Dispersion of disposed dredged slurry in the meso-tidal Changjiang (Yangtze River) Estuary 总被引：2，自引：0，他引：2
Jiaxue Wu James T. Liu Huanting Shen Shuying Zhang 《Estuarine, Coastal and Shelf Science》2006,70(4):663
To understand the dispersal pattern of sediment plume and its controlling processes, a field experiment of concentrated slurry dispersal created by a dredger was conducted in the Changjiang (Yangtze River) Estuary during the 2002 flood season. An acoustic suspended sediment concentration profiler and an acoustic Doppler profiler were deployed to simultaneously observe suspended sediment concentrations (SSC) and tidal currents at the pre-selected sections shortly following the release of dredged materials. Water sampling, grab sampling and shallow coring were simultaneously carried out to obtain the SSC and grain-size texture. High-resolution SSC profiler observations showed that two distinct sediment plumes (middle level- and near-bed plumes) occurred during the intermediate tidal phase between the spring and neap due to differential settling of the sediment mixture, whereas only a benthic plume occurred due to rapid flocculation settling during the neap tide. Three subsequent stages can be identified during the dispersal of the sediment plume: (1) initially stable stage before the release; (2) unstable stage shortly following the release as a settling cloud; and (3) stable stage after the formation of a primary lutocline or a benthic plume. Enhanced mixing due to oscillatory shear flows could raise only the elevation of the lutocline in the slurry, but could not enhance the transport capacity of suspension. In the presence of high concentration, the fate of bottom sediment plume was controlled by the bottom stress, independent of the interfacial mixing. 相似文献
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Extensive data were obtained of the water and fine sediment dynamics during spring tides in the extremely turbid Jiaojiang River estuary at spring tides. These data enabled the calibration of a two-dimensional (2-D) width-integrated model. Four processes dominated the mud dynamics. These were, firstly, the formation at slack tide of soft mud deposits with an erosion constant much smaller than that of the underlying compacted sediment, secondly the sediment-induced buoyancy effects, thirdly the collapse of the turbulence by the sediment suspension in the fluid mud range and fourthly the inflow of sediment at the mouth of the estuary. These findings demonstrate the necessity to have detailed field data to enable quantitative, as opposed to qualitative, modelling of mud dynamics in turbid estuaries. The estuary is infilling with sediment from the East China Sea and not from riverine inflow, this sediment presumably originates from the Yangtze River located 200 km further north. 相似文献
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